Packard Forum Index » Post-War (1946-54)

Quote:

It’s simply a heat chamber with no openings whatsoever to the intake or exhaust. It has a tube passing through it into which the choke line loosely fits to pull hot air up to the choke’s thermostatic spring.

The intake manifold is a replacement for the cracked one that was on the engine. The heat riser cavity had cracks on the outside face away from the engine. I believe this was due to the fact that the exhaust deflection flap was frozen in the cold position and the spring was corroded away at the stud.

I disassembled the intake/exhaust manifold assembly. I then had the exhaust and replacement manifolds sandblasted. I inspected both manifolds then sprayed 2 coats of 2000 degree primer and 3 coats of 1200 degree top paint.

I reassembled them using Grade 5 hardware and had the intake/exhaust manifolds resurfaced as an assembly. I chased the threads on all of the studs. I purchased new grade 8 nuts and equivalent thickness washers.

For initial placement and alignment I performed the following. I cut 2 pieces of (I think) 3/8" I.D. clear plastic tubing cut to the length of studs 1 and 8 and placed these on the studs. 1 and 8 are about twice as long as the others. This allowed my assistant and me to diagonally place the manifolds on the excess length of 1 and then rotate the manifolds down onto 8. The tubing then allowed us to slide the manifolds into contact with the block. Finger tight washer and nut on 3 and 6 then remove tubing.

I then followed the manual instructions to the letter when installing them (with an assistant). I purchased an offset, open-end crowfoot wrench set for use to ensure I torgued to spec on nuts including 4 and 5. 1, 3, 6 and 8 are direct access. For 2 and 7 I used a universal joint socket adapter.

I used a Max Merritt manifold gasket kit.

I’m not totally sure that using a crowfoot wrench with a torque wrench will give accurate torque due to the angle/leverage. Maybe it will but it seems that there might be some geometry involved that would require calculations. That said, I’ve never used a torque wrench on manifolds, just relying on my own experience and feel. Never had one leak and have never had a blown gasket. However, I don’t follow what the clear plastic tubing was for.

The biggest problem would happen if the two manifold faces are not in perfect flat alignment with one another. The fiber gaskets that are generally supplied have zero tolerance for any misalignment.

Packards International used to sell the thicker perforated metal wrapped gaskets and those give you a little bit of play and also were far more durable. Not sure who their supplier was, but they haven't been available for many years from from P.I.

These are what the better gaskets look like:

Looks like John Ulrich has a set from PI available for sale on ebay right now:

ebay.com/itm/205117769492?mkcid=16&mkevt ... &var=&widget_ver=artemis&media=COPY

Someone should grab these as they are NLA as far as I am aware.

"AI Overview
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A "crowfoot with a torque wrench" refers to using a crowfoot wrench (a specialized wrench with a head shaped like a crow's foot, allowing access to tight spaces) attached to a torque wrench, enabling precise tightening of fasteners in hard-to-reach areas while maintaining the specified torque level; it's crucial to position the crowfoot at a 90-degree angle to the torque wrench handle for accurate torque application."

If there is any real passage between the exhaust and intake mixture the engine will run horribly if at all, and have low or no vacuum. I would guess the smoke out of the carb is because of a pair of valves is on overlap in their cycle.

Most engine overhaul sets include a gasket for between the intake and exhaust halves. Originally that joint was metal to metal as those surfaces were freshly machined and dead flat. Here 74 years on with thousands of heat cycles plus rust and pitting, it is a good idea to use that gasket between the halves after carefully dressing the surfaces with a file. That .020 will not affect the mating of the runners to the block.

As above: "I reassembled them using Grade 5 hardware and had the intake/exhaust manifolds resurfaced as an assembly."

Thanks for the clarification Ross. I was concerned that adding the gasket would cause mating issues to the block, but good to know that it is likely not a problem.

Kunzea, might as well get that gasket and put it in. Let's see if that helps. It would be good for the rest of us to know as well.